The invention relates to a combination of a towing vehicle and an agricultural harvesting machine drawn thereby.
Agricultural harvesting machines such as balers or self-loading forage wagons, in particular, which are drawn across the field by a towing vehicle, are often used in the harvesting of green crop. Depending on the configuration and size, the harvesting machines also must be supplied with drive power by the towing vehicle in order to drive working assemblies of the harvesting machine that are used to convey and/or process the crop. In the case of a block baler, the working assemblies are, for example, the baling ram, the feed rake, possibly the cutting device, and the pick-up. Towing vehicles used in agriculture, such as tractors in particular, are equipped with a P.T.O. shaft outlet on the rear side for this purpose, which can be brought into a drive connection with a drive shaft assigned to the harvesting machine. The P.T.O. shaft outlet of the towing vehicle is usually driven by the (main) drive motor thereof. In this manner, the drive motor of the towing vehicle, the P.T.O. shaft outlet and the drive shaft of the harvesting machine form essential elements of a drive train for driving the working assemblies of the harvesting machine.
When a block baler drawn across the field by a tractor is used for harvesting, wherein the working assemblies of the block baler are driven by the tractor, it is difficult for the driver of the towing tractor to have a reliable overview of a large number of dynamically changing operating parameters, which play a role in the success of the harvesting process during the travel across the field. Factors such as the type, quantity, volume, moisture content or any other property of the picked-up crop, for example, greatly influence the harvesting process. Furthermore, machine-related factors affect the harvesting process, such as the power reserve and rotational speed of the drive engine of the tractor, the ground speed of the tractor (and the baler drawn thereby), the speed and load of individual working assemblies (e.g. pick-up, cutting rotor, feed rake, baling ram) of the press, etc.
The factors have a complex interaction with one another, in part, and usually change dynamically during the harvesting operation. Proceeding therefrom, a particular challenge for a driver is that of selecting a suitable ground speed. The selected ground speed must not be too high in order to ensure that the combination of tractor and baler can be operated during the harvesting operation with a sufficient power reserve of the drive motor in order to prevent the drive train from coming to a standstill and/or to prevent damage to the machine or injury to persons in the event that harvesting and/or operating conditions change abruptly.
In order to select such a speed that is “not too high”, the driver must take a large number of factors into consideration. In practical application, this typically results in the driver selecting a ground speed for safety reasons that is lower than would be permitted by the actual conditions. The potential output of the combination cannot be fully utilized in this case. The driver must have a great deal of knowledge and experience in order to pursue further-reaching and/or alternative objectives during the harvesting operation. An unsuitable selection of the speed can also have further disadvantageous effects, such as a poorer quality of the pressed bales (poor bale shape, crushing the crop).